Rihanna, who's often nearly-nude on her social media accounts, goes a bit more covered up for a performance in Abu Dhabi on Oct. 19. / Karim Sahib, AFP/Getty Images

by Ann Oldenburg and Arienne Thompson, USA TODAY

by Ann Oldenburg and Arienne Thompson, USA TODAY

Rihanna is channeling her inner stripper in videos and on Instagram. Britney Spears is whipping women on leashes. Nicki Minaj is braless and spilling out of her revealing jacket on Ellen. Scarlett Johansson's in her undies on the cover of Esquire. Gaga's got a thong on. And Miley Cyrus? Well, she has taught us that each and every day could bring a new tongue or twerk Twitpic from her.

Young Hollywood stars seem to have hit a new low. Why are they suddenly so oversexed, so determined to show all, so proud of parading around naked?

One answer: Because they want to.

Another: survival.

Survival of the fittest - and the sexiest. Being a dirty girl seems to be the newest movement in our pop culture evolution, as many of the hottest stars of the moment are upping the sexual ante by taking the Marilyn Monroe sex kitten idea to new, lower and raunchier levels. And a debate has erupted over this new "soft porn" normal, not just among pundits and parents, but within the industry itself.

"Every pop star wants to look sexy," says Paris Hilton, 32, whose new single and video, Good Time, features her rolling around poolside in a slinky swimsuit, arching her back and rubbing her body. It was her vision entirely, she says. "I wanted to write something that was talking about having a good time, having fun, not caring what anyone thinks and living your life."

As for those sexy moves? "When you're doing a music video, that's what it's all about." She adds, "I like doing it."

The audience seems to be enjoying it, too, says Kimberly Hairston, a beauty and fragrance marketing executive who has worked with celebrity brand ambassadors.

"We are accepting it, and we're actually almost celebrating it," Hairston says. "Miley is not on Saturday Night Live by accident. Had she not done (the Video Music Awards), they wouldn't have had her on. ... I think the audience really has dumbed down what we accept as talent. Someone's going to have to be the voice to make that shift."

It's clear that pop stars see the bar has been lowered. And not everybody's on board.

Selena Gomez, 21, told her Mohegan Sun Arena concert audience Oct. 19 in Connecticut, "Every day, I get told I'm not sexy enough or I'm not cool enough or if I did this or if I did that, I would have people who love me. Look at this room. I don't have to do any of that to have love." And to a Philadelphia concert audience last week, she said, "Let me tell you one thing, the sexiest thing I think - actually, I know - is class."

And Parks and Recreation actress Rashida Jones, 37, flat-out told the ladies to tone it down. "This week's celeb news takeaway: she who comes closest to showing the actual inside of her vagina is most popular. #stopactinglikewhores," she said in a mini-rant on Twitter. "There is a whole generation of young women watching. "Sure, be SEXY but leave something to the imagination."

Britney Spears, 31, one of the originators of the sexy-young-thing image, says she still feels pressure to turn up the heat. While chatting recently about her new provocative music video, Work Bitch, to a Boston radio show, she said, "A lot of sex goes into what I do. But sometimes I would like to bring it back to the old days when there was like one outfit through the whole video, and you're dancing the whole video, and there's like not that much sex stuff going on."

Yes, she did concede that she approved the final cut of the video. "Oh my God, we showed way more skin and did way more stuff for the video than what is actually there (in the final cut)," she admitted on The T.J. Show. "Like, I cut out half the video because I am a mother and because, you know, I have children, and it's just hard to play sexy mom while you're being a pop star, as well."

Spears isn't the only one struggling to make sense of why there's a need to show so much more skin.

Charlotte Church, a British singing sensation who became famous before she was a teen, is now 27. She said last week during a BBC-sponsored lecture that young pop stars today are "encouraged to present themselves as hypersexualized, unrealistic, cartoonish, as objects, reducing female sexuality to a prize you can win."

She recalled her own experience early on. "There was a big clamor to cover my breasts as they wanted to keep me as young as possible. Then it became, 'You should definitely get them out, they look great.' "

To some veterans in the music industry, the sexual antics are a cheap sellout.

In an Oct. 5 Facebook essay, former Eurythmics frontwoman Annie Lennox, 58, wrote that stars these days (she didn't name anyone) are behaving like "pimp and prostitute" at the same time, stooping to "misogyny" to make money.

Sinead O'Connor, 46, got into a feud with Cyrus after saying in an open letter she wrote Oct. 2 that it's not "in any way 'cool' to be naked and licking sledgehammers in your videos." She says, "You will obscure your talent by allowing yourself to be pimped, whether it's the music business or yourself doing the pimping."

But not all see the trend as a bad thing.

"I always pushed the envelope a little bit," says singer Toni Braxton, 46. "But you have to do it while you're young. How many pairs of shoes did you try on before you realized what size and style fit your leg shape? They're young, they're supposed to do that (experiment)."

"I took off my clothes in movies. I posed nude," says former child star Alyssa Milano, 40. "I did all the things that (Miley's) doing now, and I did it to continue working, to hold people's interest in what I was doing."

The Who's the Boss star is now promoting her new Project Runway All Stars hosting stint and she says, "For me, I did whatever I had to do to continue working and to stay relevant and to shatter those images of the childhood, girl-next-door star."

So is Lacey Chabert. She was 12 when she starred on the hit Party of Five drama. Now, at 31, she's on the cover of Maxim's November issue in a bra and panties, saying she wants a "long-lasting career." Jessica Biel, 31, did the same thing - posing topless for Gear magazine when she was 18 - much to the chagrin of execs at her Christian-themed drama Seventh Heaven.

Johansson - a Golden Globe nominee praised for her acting chops - accepted the mantle of Sexiest Woman Alive from Esquire and explained she needs to flaunt it while she's got it.

"You know, I gotta hustle," she said, "I'm a 28-year-old woman in the movie business, right? Pretty soon the roles you're offered all become mothers. Then they just sort of stop. I have to hedge against that with work - theater, producing, this thing with Esquire. Sounds pretty bloodless, I guess."

THE MESSAGE: 'THE VIRGIN OR THE WHORE'

The mechanics of modern celebrity still rely on one of the oldest adages in the world: Sex sells. Brigitte Bardot was a sex symbol in the 1950s and '60s, long before we came to know her as an animal rights activist. Marilyn Monroe's career was completely wrapped up in her figure and her pout. Farrah Fawcett's iconic red 1976 bathing suit poster sold 20 million copies.

Perhaps, in some ways, some of today's stars are vying to capture some of the magic of the iconic sex appeal of women who came before them, says Rebecca Collins, Ph.D., who is a member of the American Psychological Association's Task Force on the Sexualization of Girls.

"I don't know what Scarlett's thinking and doing, but she's been pretty savvy in her career, and it may just be that she thinks that this way of her branding herself is the way. She's gone a little Marilyn Monroe, and certainly her image was about sexuality as much as it was about acting, and that's maybe the way Scarlett's chosen to market herself."

But, taking a broader view, it's clear that the sexpots of yore have nothing on today's brand of writhing, grinding, gyrating titillation, Collins adds. Monroe pouted and flirted her way to the top, a far cry from Nicki Minaj's bare-breasted Instagram shot from last week.

"A lot of our sexuality now is kind of pornified; it's about stripper culture. What we see as sexy are things that really are about the buying and selling of sex, instead of what sex is really all about, which can be very healthy and a wonderful thing. We shouldn't try to eliminate it from life, it's just that we shouldn't think of it as something to be bought and sold."

Remember in 2008, when Lady Gaga burst onto the scene wowing us regularly with all things outrageous? She began carving out an image as being daring and shocking. But she was following in Madonna's sexual-envelope-pushing shoes.

The original Queen of Pop's erotic antics date to the 1980s. She, like Cyrus, made a splash on the 1984 Video Music Awards, courting controversy and launching her career singing Like a Virgin in a wedding dress. Seems tame compared with Cyrus' twerk moves, but at the time family organizations strenuously objected to the message, dubbing Madonna a "whore," while it boosted her image among fans to that of confident, sexually unashamed rule-breaker.

"Much of the lyrics of these songs have to do with sexual provocative themes, and for Miley Cyrus and all the others - Britney, Rihanna - sex is something that sells. They are looking to communicate with the masses in a way that they think will be most provocative, most intriguing and will generate the most interest," says Alan Hilfer, director of psychology at New York's Maimonides Medical Center.

And that message is harmful to young girls, Collins says.

WALKING A FINE LINE

These young, hypersexed stars are "rebroadcasting, and very effectively, a broader societal message that women's value is in their sexuality and in a particular kind of sexuality that's very objectified and commodified," Collins says.

Hairston

says losing the sexy look could shorten a woman's career life span. "If she doesn't continue that look, or be appealing in that way, her life span of (being) the leading actress could be shortened, quite frankly," she says. "Now, is it right? No. And, what's the message that we're sending to young women? That using your sexuality to sell your product or to be successful (works)."

Hairston warns against the lure of success via sex, however, noting that taking sexualization beyond the pale comes with the risk of causing a marketing backfire and alienating fans. She says this is particularly evident in the case of Rihanna's "appalling," new Pour It Up video, which features the nearly nude pop star grinding on a stripper pole.

"Someone needs to pull her back and say, 'What's really the image that you're trying to drive?' â?¦ We're not talking about Rihanna like, 'Wow, she's a genius.' We're talking about her like, 'Oh my God,' almost in a train wreck way," Hairston says of the six-time Grammy winner. "I hope that she gets back on the right track."

But, as Rihanna and Cyrus twerk their way to the top, Jane Caputi, a professor in Florida Atlantic University's Center for Women, Gender and Sexuality, says we should not be pointing the (foam) finger at them.

"You can be the virgin or the whore," Caputi says. "That's the cultural script that's laid out for women. That's what's intelligible for our culture. â?¦. You're turned by Disney into this princess or you're told in order to be an adult, turn yourself into a pornographic object. I'm sorry Cyrus feels she has to do that."

She adds, "Women should be able to have a sexual presence. We should be able to get down and dirty, but we're so negatively judged. Feminism is still needed. We haven't gotten beyond it. There's always Playboy wanting you to pose. There are forces ready to reward you when you act out, but just as ready to heap judgment and shame."

Even famous feminist Gloria Steinem, 79, blames society at large. She told Yahoo's Omg! Insider at the recent 2013 Women's Media Awards, "I wish we didn't have to be nude to be noticed, but given the game as it exists, women make decisions. ... I think that we need to change the culture, not blame the people that are playing the only game that exists."

But is it really the only game that exists? What happened to the also age-old line about "letting the work speak for itself"? Basing a career on pure talent rather than sexuality has paid off for Adele, 25, a multi-Grammy winner and chart sensation who rarely hits the red carpet wearing a dress without long sleeves. And 16-year-old pop phenom Lorde has taken the music world by storm with her hit Royals and a covered-up aesthetic.

Earlier this month, The New York Post mused, "Who's the real rebel here? A tongue-wagging Miley sitting on a wrecking ball while naked? Or Lorde, who makes music she wants to make while looking both chic and age-appropriate?"

"You know why Adele's made it? She's got a great voice, she's relatable and connect-able," says celebrity manager/casting director Marki Costello. She says Cyrus didn't need to shake things up as much as she did just to prove she's not a Disney princess. "It's a marathon, not a sprint."

Veteran music producer L.A. Reid, 57, has seen many artists rise to the top. Among those he has worked with are Braxton, Mariah Carey, Pink and Avril Lavigne. "I think they put the pressure on themselves," he says. "Because Adele is an amazing artist and sells more records than anyone and she doesn't feel the pressure to be any sexier than she is. I think that's a choice. That's an artistic choice."

Kenny "Babyface" Edmonds, 54, who recently got a star on the Walk of Fame for his work in the music industry, says there's room for everyone and whatever level of sexiness they choose to portray.

"I think every artist is their own artist. You'll have one artist that may do that, then you'll have a total different kind of artist that doesn't feel like they have to do that for the music that they do. I don't think it's wrong, per se, I just think it's kind of a sign of pop culture and the time that we're in."